This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The global spread of tuberculosis (TB) has been aggravated by the development of strains of the causative bacterium Mycobacterium tuberculosis (Mtb) that are resistant to the leading drugs. New TB therapies are urgently needed, but fortunately recent genome sequence, genetic and protein characterization studies have helped identify novel Mtb drug targets and key biochemical pathways for strategic intervention. In this regard, genes that code for lipid metabolism are a very important part of the bacterial genome, and 8% of the genome is involved in this activity. Of particular interest in the present context are the multiple cytochromes P450 (P450) encoded in the Mtb genome, whose biological roles are not yet understood. To date, physiological roles have been proposed for CYP125 CYP142 and CYP51 in sterol metabolism and for CYP132 in fatty acid metabolism, but none of these roles has been established. In this project, we intend to elucidate the function(s) of Mtb P450 enzymes, including CYP125, CYP130 and CYP141, by comparative analyses of the global lipid profiles of normal Mtb and strains in which the individual P450 enzymes have been knocked out. This comparison will be carried out using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The availability of knockout strains for these P450s makes possible a direct comparison of the lipidomic profiles under different growth and labeling conditions.